# #377ea9

A color — cool, modern. Deterministic analysis from BrandSweets (no inference).

## Values

- Hex: `#377ea9`
- RGB: rgb(55, 126, 169)
- HSL: hsl(203, 51%, 44%)
- OKLCH: oklch(0.567 0.097 238.5)
- Relative luminance: 0.186
- Nearest named color: steelblue (#4682b4, Δ 2.455) — https://brandsweets.com/colors/steelblue
- Moods: cool, modern
- Page: https://brandsweets.com/colors/377ea9

## Tints & shades

- Tints (toward white): #3d8cbd, #529ac7, #65a5cd, #7cb3d5, #8fbedb, #a3c9e1, #bad7e9, #cde2ef, #e4eff6, #f7fbfd
- Shades (toward black): #32729a, #2d678b, #285b7b, #23506c, #1e445c, #19394d, #142e3e, #0f222e, #0a171f, #050b0f

## Harmonies

- Complementary: #a96337
- Analogous: #37a99c, #3744a9
- Triadic: #a9377e, #7ea937
- Split-complementary: #a93744, #a99c37
- Tetradic: #9c37a9, #a96337, #44a937

## Colors that go with #377ea9

Named partners (harmony on the OKLCH wheel, co-occurrence in curated palettes and brand systems, and the neutrals that carry it), best first:

- **Charcoal** #36454f [role, pool] — Charcoal is the text near-black for #377ea9: softer than #000 and cool enough to feel like part of the same palette. Seen in: Beach Hut (https://brandsweets.com/palettes/light#beach-hut), Auth0 (https://brandsweets.com/colors/brands/auth0-com), Campus (https://brandsweets.com/palettes/friendly#campus), Plaid (https://brandsweets.com/colors/brands/plaid-com). — https://brandsweets.com/colors/charcoal
- **Royal Blue** #4169e1 [harmony, pool: analogous] — Royal Blue is #377ea9's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces. Seen in: Slate Workspace (https://brandsweets.com/palettes/minimal#slate-workspace), Stripe (https://brandsweets.com/colors/brands/stripe), Guinness (https://brandsweets.com/colors/brands/guinness-com), Chase (https://brandsweets.com/colors/brands/chase-com). — https://brandsweets.com/colors/royalblue
- **Rust** #b7410e [harmony, pool: split] — Rust is a split-complement of #377ea9: nearly opposite, so it still pops against it, without the vibrating edge of a true complement. Seen in: Gallery (https://brandsweets.com/palettes/editorial#gallery), Magazine Ochre (https://brandsweets.com/palettes/editorial#magazine-ochre), Semrush (https://brandsweets.com/colors/brands/semrush-com), Noir Beauty (https://brandsweets.com/palettes/dark#noir-beauty). — https://brandsweets.com/colors/rust
- **Sienna** #a0522d [harmony, pool: complementary] — Sienna sits directly opposite #377ea9 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. Seen in: Dyson (https://brandsweets.com/colors/brands/dyson-com). — https://brandsweets.com/colors/sienna
- **Amber** #ffbf00 [pool] — Amber is paired with #377ea9 in 9 real palettes, including Beach Hut and Wired's brand system, as the supporting colour. Seen in: Beach Hut (https://brandsweets.com/palettes/light#beach-hut), Wired (https://brandsweets.com/colors/brands/wired-com), Lemon Squeezy (https://brandsweets.com/colors/brands/lemonsqueezy-com), McDonald's (https://brandsweets.com/colors/brands/mcdonalds-com). — https://brandsweets.com/colors/amber
- **Blue** #0000ff [pool] — 4 real palettes, including Activision's brand system and Pixar's brand system put Blue beside #377ea9, as the accent. Seen in: Activision (https://brandsweets.com/colors/brands/activision-com), Pixar (https://brandsweets.com/colors/brands/pixar-com), Qualcomm (https://brandsweets.com/colors/brands/qualcomm-com), Readymag (https://brandsweets.com/colors/brands/readymag-com). — https://brandsweets.com/colors/blue
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #377ea9: 8 real palettes, including Hershey's's brand system and Glacier, as the supporting colour. Seen in: Hershey's (https://brandsweets.com/colors/brands/hersheys-com), Glacier (https://brandsweets.com/palettes/cool#glacier), Fintech Trust (https://brandsweets.com/palettes/cool#fintech-trust), General Mills (https://brandsweets.com/colors/brands/generalmills-com). — https://brandsweets.com/colors/cobalt
- **Crimson** #dc143c [pool] — Crimson is paired with #377ea9 in 16 real palettes, including Retro Pop and Wendy's's brand system, as the lead colour. Seen in: Retro Pop (https://brandsweets.com/palettes/playful#retro-pop), Wendy's (https://brandsweets.com/colors/brands/wendys-com), NASCAR (https://brandsweets.com/colors/brands/nascar-com), Redfin (https://brandsweets.com/colors/brands/redfin-com). — https://brandsweets.com/colors/crimson

## Contrast (WCAG 2.x, as text)

- On white (#ffffff): 4.45:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #367ba6 (4.62:1); AA: background → #080808 (4.5:1); AAA: text → #285b7b (7.31:1)
- On black (#000000): 4.72:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #599ec9 (7.16:1)

## Fonts for this mood

- modern: https://brandsweets.com/fonts/mood/modern

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/377ea9-9cb0c4-df4e5d-1f222d-e9f1f0?lock=0&style=vibrant
(Humans lock/regenerate in the tool; the URL is the state — read `lock=` back to see what they kept.)

## Connect an agent

Point any MCP client at the BrandSweets colors endpoint for the same engine:

- Endpoint: https://mcp.brandsweets.com/colors/mcp
- Tools: `analyze_color` (e.g. `analyze_color({ color: "#377ea9" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.